Download The Nervous System

Research…
• Each student should pick from the following list of
disorders to research & answer the questions on the
worksheet. Be prepared to share with the class.
o
o
o
o
o
o
o
o
o
o
o
o
Bells Palsy
Cerebral Palsy
Multiple Sclerosis
Parkinson’s Disease
Huntington’s Disease
Tay-Sach’s
Amyotrophic lateral sclerosis (Lou Gherig’s Disease)
Epilepsy
Meningitis
Alzheimer’s Disease
Muscular Distrophy
Any other nervous disorder you may find on the internet!
Do Now
• What did you learn from your skin sensitivity lab?
The Nervous
System
Chapter 9
Objectives
• To identify the basic structure of a neuron.
• To explain the main components of the nervous
system.
• To compare and contrast the central nervous
system and the peripheral nervous system.
• To differentiate between the somatic and
autonomic nervous systems.
Nervous System
• Think back to when we talked about nervous tissue.
What is it’s function? How does it go about doing
this?
• General Functions:
o Sensory (detect change)
o Integrative (make sense of it)
o Motor (cause a response)
Structure of a Neuron
• Neuron= Nerve Cell
• Reacts to physical/chemical
changes in surroundings
• Transmit information through
nerve impulses to other
neurons and other cells.
Structure of a Neuron
CNS vs. PNS
• CNS (Central Nervous System):
o Brain
o Spinal Cord
• PNS (Peripheral Nervous System):
o Cranial nerves
o Spinal Nerves
PNS
• Contains a sensory division and a motor division.
• Sensory Division:
o Contains sensory receptors that convert info into a nerve impulse
and transmit it back to the CNS to make sense of it.
o Monitors environmental changes such as light and sound
o Detects changes in homeostasis ( ex: temperature, oxygen level)
Motor Division
• Utilize peripheral neurons to carry impulses from the
CNS to an effector which will cause a response
o Ex: muscle contraction, gland secretion, etc.
Motor Division
• Somatic Nervous System:
o Controls skeletal muscle and
voluntary movement.
• Autonomic Nervous System:
o Controls effectors that are
involuntary
• Ex: heart, smooth muscle,
certain glands
Lets put
that all
together…
Do Now
• What are the 2 divisions of the nervous system?
• Name as many parts of a neuron that you can
remember.
• What are the 3 main functions of the nervous
system?
• What are the 2 motor divisions?
• What is the difference between the sympathetic
and parasympathetic nervous systems?
Objectives
• To identify and explain the 3 different structures of
neurons.
• To compare and contrast sensory, motor, and
interneurons and explain a general pathway.
• To determine the functions of the 5 types of
neuroglia.
Autonomic Nervous
System
• Parasympathetic Nervous System
o “Rest and Digest”- normal state
• Salivation
• Sexual arousal
• Lacrimation
• Urination
• Digestion
• Defication
• Sympathetic Nervous System
o “fight or flight”- triggered under stress
• Accelerated breathing & heart rate (increases blood flow)
• Inhibition or slowing of digestion
• Pupils Dilate
• Tunnel vision
• Increased muscle tension for extra strength & speed
Lets Review…
• General Neuron structure and action potential
Types of Neurons
Multipolar:
o Many processes
stemming from cell
body.
o *most neurons in
brain and spinal
cord are
multipolar
Types of Neurons
Bipolar:
o Only two
processes (one
at each end)
o *found in eyes,
nose, ears..
Types of Neurons
Unipolar:
o One single process
extending from cell
body.
o one side of axon is the
peripheral process
associated with body
part, other side is the
central process that
enters brain or spinal
cord.
o *most common type
o Involved in pain, touch,
proprioception, and
visceral organ activity
Types of Neurons
Neuron Classification
• Sensory Neurons (afferent):
o Carry impulses from PNS
to CNS
o Contain “receptor ends”
at the tips of dendrites
o Changes outside the
body stimulate receptor
ends triggering an
impulse
o *Most are unipolar
Neuron Classification
• Interneurons (association):
o Completely in brain or
spinal cord
o Link neurons together.
o Direct impulses to
appropriate parts for
processing and
interpreting
o *multipolar
Neuron Classification
• Motor Neurons
(efferent):
o carry impulses
out of brain or
spinal cord to
the effector and
stimulate
response.
o *multipolar
General Pathway
Neuroglial Cells
*More numerous than neurons,
support neurons in different
ways.
• Microglial Cells:
o Phagocytize bacterial cells and
cellular debris
• Oligodendrocytes:
o Provide insulating layers of myelin
• Astrocytes:
o Provide structural support
o join parts (ex: neuron→capillary)
o help regulate concentrations of
nutrients and ions
o Form scar tissue in the CNS
• Ependymal Cells:
o Forms membrane that covers
specialized brain parts and forms inner
linings within the brain and spinal
canal
• Schwann cells:
o Forms myelin sheath around axons.
Myelin
• A lipid that sometimes coats axons
o White matter = myelinated axons in CNS
o Gray matter = cell bodies in CNS
• Produced by some neuroglial cells
• Insulates neurons & increases
efficiency of nerve impulses
Neuroglial Cells
Reflex Arc
• Ordinarily, a receptor sends a signal to the brain
where the brain coordinates a response.
• Reflex: a rapid action that happens without thought
and does not involve the brain
• Reflex Arc: The simplest nerve pathway resulting in
reflex behavior
Reflex Arc
1)
2)
3)
4)
5)
Receptor- sense organ in skin, muscle, or other organ
Sensory Neuron- carries impulse towards CNS from receptor
Interneuron- carries impulse within CNS
Motor Neuron- carries impulse away from CNS to effector
Effector- structure by which animal responds (muscle, gland, etc).
Reflex Arc
Types of Reflexes
Babinski Reflex
• http://vimeo.com/1471
4777